Diphtheria: a serious infection of the throat that can block the airway and cause severe breathing difficulty

Tetanus (lockjaw): a nerve disease, which can occur at any age, caused by toxin-producing bacteria contaminating a wound

Pertussis (whooping cough): a respiratory illness with cold symptoms that progress to severe coughing (the "whooping" sound occurs when the child breathes in deeply after a severe coughing bout). Serious complications of pertussis can occur in children under 1 year of age, and those under 6 months old are especially at risk. Teens and adults with a persistent cough might not realize they have pertussis, and could pass it to vulnerable infants.

Immunization Schedule

DTaP immunizations are given as a series of five injections, usually administered at ages:

2 months

4 months

6 months

15-18 months

4-6 years

After the initial series of immunizations, a vaccine called Tdap (the booster shot) should be given at ages 11 to 12, or to older teens and adults who haven't yet received a booster with pertussis coverage. Then, Td (tetanus and diphtheria) boosters are recommended every 10 years. Pregnant women should also get the Tdap vaccine in the second half of each pregnancy, even if they've been vaccinated in the past.

Why the Vaccine Is Recommended

Use of the DTaP vaccine has virtually eliminated diphtheria and tetanus in childhood and has markedly reduced the number of pertussis cases.

Possible Risks

The vaccine frequently causes mild side effects: fever; mild crankiness; tiredness; loss of appetite; and tenderness, redness, or swelling in the area where the shot was given.

Rarely, a child may have a seizure or cry uncontrollably after getting the vaccine. But these sorts of side effects are so rare that researchers question whether they're even caused by the vaccine. Most kids have a few minor or no side effects.

When to Delay or Avoid Immunization

The vaccine is not recommended if your child is currently sick, although simple colds or other minor illnesses should not prevent immunization.

Talk to your doctor about whether getting the vaccine is a good idea if your child experienced any of the following after an earlier DTaP shot:

a brain or nervous-system problem, like a seizure

the worsening of a seizure disorder

an allergic reaction, like mouth, throat, or facial swelling

fever of 105°F (40.5°C) or higher during the first 2 days after injection

collapse or a "shock"-like state during the first 2 days after injection

persistent, uncontrolled crying that lasts for more than 3 hours during the first 2 days after injection

Your doctor might decide to just give a partial vaccine or no vaccine, or may determine that the benefits of vaccinating your child outweigh the potential risks.

Caring for Your Child After Immunization

Your child may experience fever, soreness, and some swelling and redness in the area where the shot was given. Depending on your child's age, pain and fever may be treated with acetaminophen or ibuprofen. Check with your doctor to see if you can give either medication, and to find out the appropriate dose.

A warm, damp cloth or a heating pad also can help reduce soreness. Moving or using the limb that has received the injection often reduces the soreness.

When to Call the Doctor

Call if you aren't sure whether the vaccine should be postponed or avoided. Children who have had certain problems with the DTaP vaccine usually can safely receive the DT vaccine.

Call if complications or severe symptoms develop after immunization, including seizures, fever above 105°F (40.5°C), difficulty breathing or other signs of allergy, shock or collapse, or uncontrolled crying for more than 3 hours.